Of mil



Nov. 6, 1928.

c, 1.. DAUN T AL REMOVABLE STATOR FOR; ELECTRIC MOTORS Original FilfiJan. 29, 1923,

INVENTORJ: Carl L. Danni, BY V aa/fjfefiefi A TTORNEY.

Reissued Nov. 6, 1928.

UNITED STATES I I "Re. 17,128 PATENT OFFICE.

CARL L. DAUN AND PAUL E. KELLER, OF MILWAUKEE, WISCONSIN, ASSIGNORS, BY

MESNE ASSIGNMENTS, TO SPLITDORF ELECTRIC COMPANY OF WISCONSIN, OE MIL-WAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

REMOVABLE STATOR FOR ELECTRIC MOTORS. 1

Original No. 1,626,028, dated April 26, 1927, Serial No. 615,685. filedJanuary 29, 1923. Application for reissue filed September 17, 1927.Serial No. 220.200

Our invention relates to removable stators for electric motors and hasfor an object the provision of a stator support capable of accuratelycentering and firmly anchoring the 5 same centrally of the frame andreadily releasable to free the stator from the frame and thus permit thesame to be easily withdrawn axially from within the frame. This weaccomplish by the use of a series of spacer elements or keys which aredriven into firm contact with and between the stator and frame and coacttherewith to accurately center and firmly anchor the stator and whichare removable to thereby provide ample clearance to permit freewithdrawal of thestator.

For. this and other purposes which will hereinafter appear the motorframe shown and hereinafter specifically described is providedinteriorly with a plurality ofcprojections, the latter I being spacedabout the frame, and also at one end with inwardly pro-' jecting lugswhich receive bolts passing through the stator to position and retainthe latter properly in the frame. The said projections are preferablygrooved on their op posite faces for the reception of removable keys bymeans of which the stator 15 maintained' in concentric relation to theaxis of the shaft of the motor. Caps are applied to the ends of theframe to form journals for the motor shaft and complete the structure.

Having thus outlined the general nature of our invention, we will nowproceed to a specific description of the same, and will point out thenovelty thereof in the appended claims.

Referring to the accompanying drawing: l Figure 1 is a' view inelevation, with parts 40 in section, of our improved motor.

Fig. 2 is a horizontal Section on the line 2-2, Fig. 1, looking in thedirection of the arrows. .howing the construction, and arrangement ofthe parts embodied in our 1mprovement.

In the drawing, the numeral 10 indicates the frameof our motor, the saidframe being open from end to end. Gaps 11 and 12, of any suitableconstruction may be secured to the ends of the frame so as to completethe structure. The shaft 13'of the rotor 14 is journaled in bearingsformed in the said caps. Fans 15, supported on the shaft 13, one

at each end of the rotor, are arranged for effecting a forcedcirculation of air through the motor and prevent overheating.

The motor f ramc is provided interiorly with a (:irrumi'erential channel14, through which the air is circulated by the fans while the motheframe and also axially with respect to the center line thereof. Theseprojections 15 are machined so as to'produce preferablygrooves 16 whichlatter are formed on lines parallel with each other and aligned axiallywith the rotor so that the bottom of such grooves will standsubstantially concentric with the axis of the rotor, when the parts ofthe motor are assembled.

The outer diameter of the laminated stator ring 17 isslightly less thanthe shortest distance between opposite projections 15, so that thestator may be easily slipped into its position in the motor frame. Thelaminations of the stator core or ring 17 are clamped together by meansof clamping bolts 20 and nuts 21 coacting with the threaded bolt endsand with the core end. Keys 18 are driven into the grooves 16 of theprojections, and engage the stator ring at several points upon itscircumference, so that the stator ring is ac curately centered withrespect to the rotor. The side Walls of the grooves 16 constitute meansfor confining the keys 18 against lateral displacement, and the keys 18may have a slight wedging action, but this provision is not regarded asessential to successful installation.

.The interior of the motor frame is provided with a series of inwardlyprojecting lugs 19 having holes adapted to receive the projectingthreaded ends of the clamping bolts 20. After the stator core or ring 17has been positioned within the frame 10, nuts 22 may be applied to thethreaded bolt ends to lock the stator core and its winding within theframe and to prevent rotation thereof.

In removing the stator, in case necessity therefor arises, it isnecessary only to drive out the keys 18 and loosen the end nuts 22 ofthe bolts 20 which hold the stator against the lugs 19, after removingthe end caps and withdrawing the rotor. A wrench, a drift and a. hammerare the only tools required in performing this operation. I Removal of apart only of the keys will sufliciently relieve V the stator of itsbinding pressure, and permit its removal with its windingas a unit fromthe frame. As hereinbefore stated, the time required for replacement ofthe stator winding is very small, and consequently it is not necessaryto ship the motor for re- Winding in the event that the latter becomesunserviceable. In a plant using several motors of uniform construct-ion,reserve stators may be kept in stock, but in the absence of a reservestator, a new one can be obtained and replacement effected in much lesstime than the old one can be re-wound.

Having thus described our invention, what we claim and desire to secureby Letters Patent of the United States is:

1. In an electric motor, a frame, a stator and a rotor, mounted therein,the said frame being provided interiorly with a plurality ofcircumferential rows of grooved projections concentrically and axiallyaligned with i respect to the rotor, and locking keys, each engagingaplurality of the aligned grooved projections and the stator, to positionthe latter concentrically with relation to the rotor, whereby uponremoval of the said keys the stator and its winding as a unit may bewithdrawn from the frame.

2. In an elecrt-ic motor, a frame having a series of inwardlyextending-projections and an intervening series of inwardly extendinglugs, a laminated stator core disposed within said frame and having itsperiphery spaced from said projections, said core-being provided withlamina: clamping means attachable to said lugs to prevent endwise displacement of said core, and a core positioning key spanning the spacebetween each of said projecti'ons and theperiphery of said core tomaintain said core centrally within said frame.

3. In an electric motor, a framehaving a series 0f inwardly extendingprojections and an intervening series of inwardly extending 'lugs, ,/alaminated stator core disposed withmpSaid frame and having its peripheryspaced from said projections, said core being provided with laminaeclamping means attachable to said lugs to preventendwise displacement ofsaid core, a plurality afgperallcl co" positioning keys spanning pencenti ally within said frame, and means oowith the sides of said keys tomaintain said keys parallel to each other and to the stator is, V

4, In an electric motor the combination of a frame member, a statormember, one of said members having a circular series of projectionsextending toward but peripherally spaced from said other member, andspacer between said projections and the 1 cry of said core to maintainsaid core spaced from said other member, spacer keys driven lengthwiseinto binding contact between said projections and said other member a toaccurately center and positively anchor said stator member within theframe, and interlocking means between said keys and projections forholding said keys against lateral displacement but permitting lengthwiseremoval of said keys to render said stator mem ber freely withdrawablefrom the frame.

6. In an electric motor the combination of a frame member a statormember, one of said members having a plurality of axially spacedcircular series of projections extending to-- ward said other member andproviding a substantially unobstructed, air passage between saidmembers, and keys removably interposed between said projections and saidother member and coacting with each other and said projections toaccurately center and positively anchor said stator member within theframe. v w s 7. In an electric motor the combination of a framestructure, a stator structure, a rotor therein, one of said structuresbeing provided with a plurality of circumferential rows of groovedprojectionsconcentrically and axially aligned with respect to saidrotor, and lockmg keys each enga g a plurality of the aligned groovedpro ections and the other of said structures to position said statorstructure concentrically with relation to said rotor, whereby uponremoval of the said keys the stator structure may be withdrawn as a unitfrom said'frame structure.

8. In an electric motor the combination of a stator core, a framehousing said core and peripherally spaced therefrom to provide acircumferential air passage thereabout, aseries of projections extendinginwardly from said frame toward the periphery of said core,

and elements removably interposed inbinding contact with and betweensaid core and projections to provide a positive centering means for saidcore releasable to permit free removal of said core as a unit, saidprojections and elements being shaped and ar ranged toavoidlinterrupting the continuity of said circumferential In witneswhereof, we hereunto subscribe our names this 1st day of September,1927.

" CARL L. DAUN.

